Brazilian Journal of Physics最新文献_第7页

Modulational Instability of Dust Acoustic Waves in Non-Maxwellian Strongly Coupled Dusty Plasmas 非麦克斯韦强耦合尘埃等离子体中尘埃声波的调制不稳定性

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-09-09 DOI: 10.1007/s13538-024-01595-8

Mahmood A. H. Khaled, Mohamed A. Shukri, Kholood A. AL-Shawafi

引用次数: 0

Instantons and Transseries of the Mathieu Potential Deformed by a (mathcal{P}mathcal{T}) Symmetry Parameter 由$$mathcal{P}mathcal{T}$对称参数变形的马修势能的瞬子和跨序列

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-09-07 DOI: 10.1007/s13538-024-01593-w

Natália M. Alvarenga, Erich Cavalcanti, Cesar A. Linhares, José André Lourenço, José Roberto P. Mahon, Fernando P. P. Reis

{"title":"Instantons and Transseries of the Mathieu Potential Deformed by a (mathcal{P}mathcal{T}) Symmetry Parameter","authors":"Natália M. Alvarenga, Erich Cavalcanti, Cesar A. Linhares, José André Lourenço, José Roberto P. Mahon, Fernando P. P. Reis","doi":"10.1007/s13538-024-01593-w","DOIUrl":"10.1007/s13538-024-01593-w","url":null,"abstract":"<div>We investigate the non-perturbative effects of a deformation of the Mathieu differential equation consistent with ({varvec{mathcal{P}mathcal{T}}}) symmetry. First, we develop a connection between the non-Hermitian and Hermitian scenarios by a reparameterization in the complex plane, followed by a restriction of the ({varvec{mathcal{P}mathcal{T}}}) deformation parameter. The latter is responsible for preserving the information about ({varvec{mathcal{P}mathcal{T}}}) symmetry when we choose to work in the Hermitian scenario. We note that this factor is present in all non-perturbative results and in the transseries representation of the deformed Mathieu partition function that we have obtained. In quantum mechanics, we found that the deformation parameter of ({varvec{mathcal{P}mathcal{T}}}) symmetry has an effect on the real instanton solution for the deformed Mathieu potential in the Hermitian scenario. As its value increases, the non-Hermiticity factor makes it smoother for the instanton to pass from one minimum to another, that is, it modifies the instanton width. The explanation for this lies in the fact that the height of the potential barrier decreases as we increase the value of the deformation parameter. We present how this effect extends to the multi-instanton level and to the bounce limit of an instanton-anti-instanton pair. As an application of the obtained results, we show that the equation of motion under a tilted version of the potential in the Hermitian scenario compares to the resistively shunted junction (RSJ) model for the Josephson junction.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"54 6","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of the Fear Factor and Prey Refuge in an Asymmetric Predator–Prey Model 非对称捕食者-猎物模型中恐惧因素和猎物庇护所的影响

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-09-06 DOI: 10.1007/s13538-024-01594-9

Rasha M. Yaseen, May M. Helal, Kaushik Dehingia, Ahmed A. Mohsen

引用次数: 0

Design and Analysis of Triangular Split-Ring Resonator–Based Patch Antenna for High-Speed Terahertz Devices 用于高速太赫兹设备的基于三角形分环谐振器的贴片天线的设计与分析

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-09-04 DOI: 10.1007/s13538-024-01597-6

A. Sivasangari, Sathish Kumar Danasegaran, S. Dhanasekar, Elizabeth Caroline Britto, M. Paranthaman

引用次数: 0

Schwinger Pair Production in QCD from Flavor-Dependent Contact Interaction Model of Quarks QCD中的施文格对产生源自夸克的味依赖性接触相互作用模型

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-09-03 DOI: 10.1007/s13538-024-01581-0

Aftab Ahmad, Akif Farooq

{"title":"Schwinger Pair Production in QCD from Flavor-Dependent Contact Interaction Model of Quarks","authors":"Aftab Ahmad, Akif Farooq","doi":"10.1007/s13538-024-01581-0","DOIUrl":"10.1007/s13538-024-01581-0","url":null,"abstract":"<div>We study the Schwinger mechanism in QCD, which refers to the production of quark-antiquark pairs in the presence of a pure electric field strength eE, for a higher number of colors (N_c) and flavors (N_f). Our unified formalism is based on the Schwinger-Dyson equations, a flavor-dependent symmetry-preserving vector-vector contact interaction model of quarks, and an optimal time regularization scheme. For fixed (N_c=3) and (N_f=2), the dressed quark mass decreases as we increase eE, and near or above the pseudo-critical electric field (eE_c), the chiral symmetry is restored, and quarks become deconfined. The pair production rate (Gamma) becomes stable and grows quickly above (eE_c). For fixed (N_c=3) and upon increasing (N_f), the dynamically generated mass suppresses, and as a result, the (eE_c) reduces to smaller values, and the pair production rate (Gamma) tends to initiate and grow quickly for smaller values of (eE_c). In contrast, for fixed (N_f=2) and upon increasing (N_c), the chiral symmetry is restored for larger and larger values of (eE_c); and for (N_cge 4), the transition changes from smooth cross-over to the first order at some critical endpoint ((N_{c,p}, eE_{c,p})). Consequently, the quark-antiquark production rate (Gamma) requires higher values of (eE_c) for stable and quick growth as we increase (N_c). Our findings are satisfactory and in agreement with the already predicted results for the pair production rate (for fixed (N_c=3) and (N_f=2)) by other reliable effective models of QCD.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"54 6","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Possibility of Discovering the Super-Heavy Elements Z=119 and 120 发现超重元素 Z=119 和 120 的可能性

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-08-29 DOI: 10.1007/s13538-024-01551-6

H. C. Manjunatha, N. Sowmya, P. S. Damodara Gupta, N. Manjunatha, T. Nandi

{"title":"Possibility of Discovering the Super-Heavy Elements Z=119 and 120","authors":"H. C. Manjunatha, N. Sowmya, P. S. Damodara Gupta, N. Manjunatha, T. Nandi","doi":"10.1007/s13538-024-01551-6","DOIUrl":"10.1007/s13538-024-01551-6","url":null,"abstract":"<div>We reveal that inclusion of fission barrier, nuclear level densities, neutron and fission decay widths in a better way in the advanced statistical method and dinuclear system model can lead to reproduce well the measured production cross sections of the cold and hot fusion reactions in the range (Z=102-118). In addition, we show that the optimal beam energies, where the production cross section reaches its maximum, can also be effectively determined using quasielastic barrier distribution curves. This theoretical approach helps us to verify the cause of low production cross section measured for the super-heavy element (SHE) (^{278})Nh with the reaction (^{70})Zn + (^{209})Bi and null results from the reaction (^{86})Kr+(^{208})Pb used for synthesizing the SHE Z=118. Furthermore, the same has been employed to explore the reason for the failure of many trials in synthesizing the SHEs for (Z=119) and 120. ER cross sections at the optimal energies for a few heavy-ion reactions in synthesizing the SHE (Z=119) and 120 are seen to be measurable. Thus, the synthesis of the SHEs for (Z=)119 and 120 is on the cards.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"54 6","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Anisotropic Fractional Brownian Field Synthesis via Curvelet Transform 通过曲线小波变换合成各向异性的分数布朗场

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-08-29 DOI: 10.1007/s13538-024-01580-1

M. V. C. Henriques, F. E. A. Leite

引用次数: 0

An Investigation on Structural, Optical, Thermal, and Dielectric Analysis of L-Lysine Iodide Semiorganic Nonlinear Optical Single Crystal for Opto-electronic Application 用于光电应用的 L-赖氨酸碘化物半有机非线性光学单晶的结构、光学、热学和介电分析研究

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-08-28 DOI: 10.1007/s13538-024-01588-7

P. Revathi, T. Balakrishnan, J. Thirupathy

{"title":"An Investigation on Structural, Optical, Thermal, and Dielectric Analysis of L-Lysine Iodide Semiorganic Nonlinear Optical Single Crystal for Opto-electronic Application","authors":"P. Revathi, T. Balakrishnan, J. Thirupathy","doi":"10.1007/s13538-024-01588-7","DOIUrl":"10.1007/s13538-024-01588-7","url":null,"abstract":"<div>A single crystal of L-lysine iodide (LLI) was created by utilizing a room-temperature slow evaporation approach. The monoclinic of the crystal lattice system was confirmed by estimating the lattice parameters of the synthesized single crystals using single crystal X-ray diffraction analysis. The crystalline structure and planar indexing were confirmed by powder XRD. In order to confirm that the produced LLI crystals included functional groups, the FT-IR spectra were analyzed. Spectra of visible, near-infrared, and ultraviolet light (ranging from 200 to 1100 nm) were analyzed and the cutoff wavelength of 268 nm. Vickers microhardness tester was used to find out how strong the formed crystal was mechanically stable. From 50 Hz to 3 MHz, the dielectric response of the manufactured crystal was studied at different temperatures. Thermogravimetric analysis used to look at the thermal characteristics. Human pathogens were the primary focus of antimicrobial research. Using scanning electron microscopy (SEM), the surface characteristics of the generated crystal were examined. The produced LLI crystal was recommended for use in opto-electronic and biological applications.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"54 6","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Giant Dielectric Permittivity and Electronic Structure in Hydrogenated (La/Mn) Merge Codoped TiO2 Ceramics 氢化（La/Mn）并合掺杂二氧化钛陶瓷中的巨介电常数和电子结构

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-08-27 DOI: 10.1007/s13538-024-01582-z

A. A. Dakhel

{"title":"Giant Dielectric Permittivity and Electronic Structure in Hydrogenated (La/Mn) Merge Codoped TiO2 Ceramics","authors":"A. A. Dakhel","doi":"10.1007/s13538-024-01582-z","DOIUrl":"10.1007/s13538-024-01582-z","url":null,"abstract":"<div>Titanium oxide (TiO2) nanoparticles (NPs) codoped with (La/Mn) ions were synthesized by a hydrothermal decomposition technique. The prepared codoped NPs were hydrogenated at 400 °C and systematically studied by X‐ray diffraction (XRD), optical diffuse reflection spectroscopy (DRS), and electrical insulating measurements. The codoped solid solution (SS) NPs were prepared to be built of core/shell-like electronic nanostructures that having giant permittivity (GP) of order 104, which is extremely higher than that of undoped TiO2. The electronic nature of the built structures was described according to the foundation of the doping mechanisms. Thus, the codoping was employed in the present work to fabricate coalesce dielectric crystalline medium of GP. Two Mn-dopant concentrations were used in the present investigation for comparison. Thus, the objective of creation of GP properties was successfully achieved. Moreover, the results of the electrical measurements were analyzed according to the available models: the correlated barrier hopping (CBH) model, the polarons-hopping conduction model, and Jonsher’s AC power law.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"54 6","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An Emerging Strategy in Sequential Synthesis of Catalyst and Carbon Nanotube Foams by Employing a Chemical Vapor Deposition Procedure: Structural Evaluation and Growth Mechanism 采用化学气相沉积程序依次合成催化剂和碳纳米管泡沫的新策略：结构评估与生长机理

IF 1.5 4区物理与天体物理

Brazilian Journal of Physics Pub Date : 2024-08-27 DOI: 10.1007/s13538-024-01583-y

J. Logeswari, T. Kamatchi, P. Kumaresan

{"title":"An Emerging Strategy in Sequential Synthesis of Catalyst and Carbon Nanotube Foams by Employing a Chemical Vapor Deposition Procedure: Structural Evaluation and Growth Mechanism","authors":"J. Logeswari, T. Kamatchi, P. Kumaresan","doi":"10.1007/s13538-024-01583-y","DOIUrl":"10.1007/s13538-024-01583-y","url":null,"abstract":"<div>In an effort to further expand the simplification of the bulk production of carbon nanotube (CNT) foams, herein, a new approach based on one-step synthesis procedure is developed, where the production of the catalyst is followed by CNT foam growth in a chemical vapor deposition (CVD) furnace during acetylene decomposition over three various mole ratios of Fe: Mo: MgO: PEG (polyethylene glycol) sol-gel viscous precursor catalyst (viz., 1: 0.5: 13: 4.8, 1: 1: 13: 5, and 1: 1: 50: 17.3) under Ar/H2 atmosphere at various reaction conditions. The growth of multi-walled CNT foams was directly carried out, i.e., without preceding any reduction and oxidation phases over viscous gels. The various parameters such as molar ratio, reaction temperature, and acetylene flow rate were optimized individually for the production of ultra-lightweight foamed CNTs. The CNT foams grown from the optimized reaction conditions were discussed by using various physicochemical characterization studies, such as XRD, FT-Raman, SEM, TEM, FE-SEM with EDX, N2 sorption isotherms, and thermal analysis. The issues regarding the growth mechanism of high specific surface area CNT foams are taken in the present approach. Such a mechanism has been proposed for the carbo-thermal reduction of acetylene over the optimized viscous catalyst precursors gel at 800 °C in a CVD furnace.</div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"54 6","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142193811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0